/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2011 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#import <QuartzCore/QuartzCore.h>

#import <OpenGLES/EAGLDrawable.h>

#import "SDL_uikitopenglview.h"

@interface SDL_uikitopenglview (privateMethods)

- (BOOL) createFramebuffer;

- (void) destroyFramebuffer;

@end

@implementation SDL_uikitopenglview

@synthesize context;

+ (Class)layerClass {

    return [CAEAGLLayer class];

}

- (id)initWithFrame:(CGRect)frame \

      retainBacking:(BOOL)retained \

      rBits:(int)rBits \

      gBits:(int)gBits \

      bBits:(int)bBits \

      aBits:(int)aBits \

      depthBits:(int)depthBits \

      majorVersion:(int)majorVersion \

{

    NSString *colorFormat=nil;

    BOOL useDepthBuffer;

    if (rBits == 8 && gBits == 8 && bBits == 8) {

        /* if user specifically requests rbg888 or some color format higher than 16bpp */

        colorFormat = kEAGLColorFormatRGBA8;

    }

    else {

        /* default case (faster) */

        colorFormat = kEAGLColorFormatRGB565;

    }

    if (depthBits == 24) {

        useDepthBuffer = YES;

        depthBufferFormat = GL_DEPTH_COMPONENT24_OES;

    }

    else if (depthBits == 0) {

        useDepthBuffer = NO;

    }

    else {

        /* default case when depth buffer is not disabled */

        /* 

           strange, even when we use this, we seem to get a 24 bit depth buffer on iPhone.

           perhaps that's the only depth format iPhone actually supports

        */

        useDepthBuffer = YES;

        depthBufferFormat = GL_DEPTH_COMPONENT16_OES;

    }

    if ((self = [super initWithFrame:frame])) {

        // Get the layer

        CAEAGLLayer *eaglLayer = (CAEAGLLayer *)self.layer;

        eaglLayer.opaque = YES;

        eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:

                                        [NSNumber numberWithBool: retained], kEAGLDrawablePropertyRetainedBacking, colorFormat, kEAGLDrawablePropertyColorFormat, nil];

        if (majorVersion > 1) {

            context = [[EAGLContext alloc] initWithAPI: kEAGLRenderingAPIOpenGLES2];

        } else {

            context = [[EAGLContext alloc] initWithAPI: kEAGLRenderingAPIOpenGLES1];

        }

        if (!context || ![EAGLContext setCurrentContext:context]) {

            [self release];

            return nil;

        }

        /* create the buffers */

        glGenFramebuffersOES(1, &viewFramebuffer);

        glGenRenderbuffersOES(1, &viewRenderbuffer);

        glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);

        glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);

        [context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer*)self.layer];

        glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);

        glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);

        glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);

        if (useDepthBuffer) {

            glGenRenderbuffersOES(1, &depthRenderbuffer);

            glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);

            glRenderbufferStorageOES(GL_RENDERBUFFER_OES, depthBufferFormat, backingWidth, backingHeight);

            glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);

        }

        if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {

            return NO;

        }

        /* end create buffers */

        // !!! FIXME: use the screen this is on!

        /* Use the main screen scale (for retina display support) */

        if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])

            self.contentScaleFactor = [UIScreen mainScreen].scale;

    }

    return self;

}

- (void)setCurrentContext {

    [EAGLContext setCurrentContext:context];

}

- (void)swapBuffers {

    glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);

    [context presentRenderbuffer:GL_RENDERBUFFER_OES];

}

- (void)layoutSubviews {

    [EAGLContext setCurrentContext:context];

}

- (void)destroyFramebuffer {

    glDeleteFramebuffersOES(1, &viewFramebuffer);

    viewFramebuffer = 0;

    glDeleteRenderbuffersOES(1, &viewRenderbuffer);

    viewRenderbuffer = 0;

    if (depthRenderbuffer) {

        glDeleteRenderbuffersOES(1, &depthRenderbuffer);

        depthRenderbuffer = 0;

    }

}

- (void)dealloc {

    [self destroyFramebuffer];

    if ([EAGLContext currentContext] == context) {

        [EAGLContext setCurrentContext:nil];

    }

    [context release];    

    [super dealloc];

}

@end

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